DE1494048A1 - Process for the production of solutions from acrylonitrile polymers in organic solvents - Google Patents

Description

In the production of acrylonitrile polymer solutions that are suitable for the production of shaped articles, yellowing always occurs. Namely, it is for manufacturing such solutions necessary to achieve high concentrations, for which long solution times and generally increased Solution temperatures required.

It is already known solutions of acrylonitrile polymers Add stabilizers to avoid yellowing as much as possible. So it is known to use acidic compounds as stabilizers to use. Such additives are mainly intended to reduce the harmful influence of basic decomposition products as solvents

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Turn off serving dimethylformamide. However, now that large-scale processes are known that allow “very pure” To produce dimethylformamide is the area of application of the named Stabilizers severely restricted. Besides, it is not possible ' to obtain really colorless polymer solutions with these additives.

The yellowing of polyacrylonitrile solutions is due to other chemical · Reactions as e.g. yellowing of polyvinyl chloride. Polyvinyl chloride can be stabilized very well with compounds that act as hydrogen chloride acceptors are. Such compounds cause, however, particularly strong yellowing in the case of polyacrylonitrile solutions. The yellowing of diolefin polymers and diolefin copolymers is also due to which is prevented by common radical scavengers, such as polyvalent phenols, on a different mechanism than the browning of Polyacrylonitrile solutions. There are practically no olefinically unsaturated carbon double bonds in polyacrylonitrile, and the starting points of a crosslinking or an oxidation reaction are not given in the case of polyacrylonitrile polymer solutions.

Due to the differences in the degradation mechanisms, the stabilizers effective for the individual polymers polymer-specific. Stabilizers, which are used e.g. in polyvinyl chloride are very effective, but prove to be ineffective in the case of aoryl nitrile polymer solutions.

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It is also known to carry out the dissolving process itself in a manner that is as gentle as possible in order to produce acrylonitrile polymer solutions that are as light as possible. For this purpose, a nonsolvent is added to the solvent. If the acrylonitrile polymer is introduced into this mixture, a suspension is initially formed. When the mixture is heated, the dispersed polymer particles dissolve relatively quickly. The nonsolvent is removed from the solvent. Can for this method A are as non-solvent organic solvents used not resolve which acrylonitrile polymers, as well as acid anhydrides such as Schwefelsäuredioxyd and carbon dioxide. In order to reduce this dissolving power of a solvent to the necessary extent by adding sulfur dioxide, about 17 to 85 % sulfur dioxide, based on the polymer, must be added (see, for example, German patent specification 972 816).

The production of the lightest possible acrylonitrile polymer solutions

following this particular dissolution process has various disadvantages on. So the profitability is relatively low, since the nonsolvents have to be recovered from the solutions in order to get back again can be used. In addition, there are disadvantages when using sulfur dioxide as a nonsolvent, since in this If the recovery of the nonsolvent is already hygienic Reasons must be carried out as completely as possible. This also requires a large outlay in terms of equipment.

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It has now been found that solutions of polymers can be used Acrylonitrile «Effectively stabilize in organic loungewear wraps can, if you connect to the air service process in Oejjenwart with the formula

makes in which

R. and Rp stand for hydrogen, alkyl and aryl, R * for WaeseratoiT, alkyl, a polar or

polar divisible radical, such as phenyl, halogen, cytm,

Ketoalkyl, carbalkoxy and alkylsulfonyl, R ·. for a polar or polarizable red,

such as phenyl, halogen, cyano, ketoalkyl, carbalkoxy

and alkylsulfonyl,

Rc for any organic radical, preferably

vfi i se for

\ ? 1

~ .. - C - stands,

where R. η for O ¹

. to R ₁ . have the indicated meaning and t 1 ode? 2 stands «'

Suitable sulfones, sulfoxides and thioethers, which at the a-C-Atora through polar groups are substituted, can be found, inter alia, in D ^ Pil 026 526 and. DAS 1 030 561. Selenium mentioned as examples!

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08 U94CU8

C ₂ H ₅ -S0 _s -CH _p -CH _? CN

₀ ( ₀₀

ti € egg

C ₀ H _n -SO ₀ -CH ₀ -CH-CN

-. V> r egg ι

\ ti

CH-,

C ₆ H ₅ -SOp-CHp-CH-C ₆ H ₅ CH ₅

SOp- (CH ₂ -CH (CN) ₂ ) ₂

CH, -S0 _o -CH-CH (CN), CH ₃

SO ₂ - (CH-CH (CN) p) p CH,

.COCH

^ H _R -S0 ^ -CH _o -CHC ⁶ 5 ^ 2

^ CO-CH ^S ° - ^(CH 2 ^CH -C0-Ch

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copy

BAD ORfGINAL

K94048

^ CO-CH ₃

) ₂

.COCH, SO ₉ - (CH ₉ -CH / ^ -5) p

* ^d ^ COOCH,

.COCH,
SO ₉ - (CH-CH ^ ^) "

^C00CH 3

C; ) ₉

^C00CH

.COCH, COOCH

CH ₃ //

COCH, COOC ₉ H,

y- <. .COCH,

CH 0 // Vs.-SO ₉ -CH ₉ -CH ^ '

j / COCH CH, 0- ^ ^ -SO ₉ -CH ₉ -CH ^ -

f. .C0CH_

CH ₃ O- J / \ -CH ₂ -SO ₂ -CH ₂ -CHr

Vsass /

CH '->

^ COOCH ₃

CO-CH ^

2 \

CK, ^ \ -SO ₂ -CH ₂ -CH '

"" ^Swi 2 909 8 21/1162

H940A8

Have the mentioned sulfones, sulfoxides and thioethers as such, different thermal resistances or different decomposition temperatures and allow it therefore, to use the optimal component for different temperature loads. The higher the Temperature, the higher the decomposition temperature of the stabilizer should be. The decay lets through Additives such as β-dicarbonyl compounds, quaternary ammonium or sulfonium salts, carboximides, dicarboximides, such as. B. phthalimide, and other compounds catalytically accelerate with activated hydrogen atoms, such as sulfinic acids. Are advantageously suitable for this purpose sulfinic acids, those on the ß-C atom with negative

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Groups substituted and thereby become stable as free acid, e.g. HO ₂ S ₀ CH (CH ^) - CH (COCH ₅ ) COOc ₂ H ₅ . It is also advisable to add complexing agents for heavy metals in amounts of 0.001 to about 0.1 t, based on the polymer, to the solutions, such as ethylenediaminetetraacetic acid, nitrilotriacetic acid, 1, g-diamino-cyclohexanetetraacetic acid, diethylenetriamine-pentaacetic acid, uramil-N ^ N-diacetic acid, 2-hydroxyethyl-ethylenediamine triacetic acid, pyrocatechic, resoroic and hydroquinone disulfonic acid.

The addition of the stabilizers can be done so that a highly concentrated stock solution via a metering device with the Solvent for the polymer in a dissolving screw or a Ltsek-essel is united. Man. can also use the stabilizers add the polymer together into the solvent.

The solutions obtained can be used immediately or after deaeration. or filtration can be added to the deformation process. the Stabilized solutions obtained according to the invention show against * a number of advantages over the previously known solutions. Despite the use of the usual dissolution conditions, they are colorless. she can also be used for a longer period of time, possibly at higher temperatures, be stored without yellowing or the formation of Qelkkörpers occurs.

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Old aoryl nitrile polymers include both homopolymers and copolymers with a predominant amount of acrylonitrile, for example those with acrylic acid esters, methacrylic acid esters, vinyl acetate, acrylic acid amide, methacrylic acid amide, styrene, vinyl pyrrolidone, vinyl pyridine and other basic components, styrene sulfonic acid and other basic components their acidity is comparable to that of styrene sulfonic acid. Preference is given to using polymers with at least 80 % bound acrylonitrile.

Suitable solvents for the polymerisation ⁴ - come except dimethylformamide di · usual polar compounds in question, such as dimethyl acetamide,

Ethylene glycol carbonate and dimethyl sulfoxide.

- ι

The dissolving temperature is generally between 10 ° and 100 °, preferably between 30 and 35 °. The content of the solution in the polymer is between 5 and 35%. The amounts of stabilizer can vary between wide Oranzen and Hegern generally between 0.01 and about 2%, whereby the solubility limit should not be exceeded, advantageously between 0.11 %. The amounts depend ■ Loh and more for the duration of the embossing korkenden in thermal stress, for example after the duration of the dissolution process and Nasr. the temperature used. The polymer solutions obtained are colorless in the presence of the stabilizers or stabilizer combinations mentioned and, like the finished molded objects , can be stored for a long time at a higher temperature without yellowing.

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Example 1 ι ·

Its 10 ^ term solution of a copolymer of 95 XIn. Acrylonitrile and 5 TIn. Acrylic acid methyl ester is in dimethylformamide with and made without any following additives and 16 hours at Aged 80 °. The following are then displayed in the electrolytic capacitor photometer Measured extinctions »

E / d at * - 450 470 530 620 ■ / ».

without addition 0.363 0.286 0.081 0.024

COCH ₁ with 0.1 + SO, (-CH ₁ -CHC ₀₀₀₁ J ₈ ). 0.305 0.255 0.081 0.018

with p, 25 # "0.251 0.194 0.063 0.019

with 0.5 £ "0.164 0.124 0.038 0.015

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Example 2 :

XO £ ige Lttsuag a ·· Copolymers of · 95 Tin. Acrylonitrile and 5 tin. Acrylic acid ethyl ester

la Diaethylforaaaid ait and without the following additives and aged for 16 hours at 80 *.

the extinctions given in the table are generally measured by Blko-Fhotoaeter *

without addition

old 0.05 f hm

Old 0.25 Jt S0 _a -CH _t CH _t CS) _t

«It 0.25 * G ₁ H.CH ₁ -SO, -CH ₁ CH, CI

COOC ₁ H ₁ old 0.25 β Ci-CH ₁ CH ₁ -SO ₁ -CH-CH ^ ₀₀ U

' ^: - CH ₁ '

^^ ^ COOC H _{1 1}

old 0.25 ^ CH ₁ 0 »° t - ^" ⁰¹ SJOCH ₁

C ₁ H ₁ CH ₁

Bit 0.25 # HC-Ö-SO.-CH.-CH ' ⁰⁰⁰⁰⁰

• Ci ₁ ^C0CH »

old 0.25 51 CH ₁ O-OSO ₁ -CH-CH ' ⁰⁰⁰⁰ ^

CH ₁ ^NC00H

with 0.25 * CH ₁ 0-0-SO ₁ -CH ₁ -CH " ^000CH ·

^ JOCH

old 0.25 % CH ₁ 0-OCH ₁ -SO, -CE, -CH ' ⁰⁰⁰⁰¹¹ »

^V COCH «

at λ - 450 470 530 620 ψ

0.300 0.234 0.073 0.026

0.264 0.211 0.075 0.027

f 0.05 1 » Ae 0.209 0.172 O., O55 0.022

+ 0.05 # At 0.254 0.203 0.071 0.028

⁺ 0.05 % Ae 0.215 0.172 0.052 0.018

+ 0.05 % Ae 0.217 0.182 0.043 0.020

+ 0.05 + Ae 0.158 0.129 0.038 0.012 + 0.05 # AE 0.148 0.120 0.034 0.007 + 0.05 ^ Ae 0.170 0.138 0.037 0.007 + 0, o5 1> AE 0.149 0.123 0.037 0.009

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- 13 - Example 3 .

lint 10% solution in a copolymer of 95 tin. Acrylonitrile and 5 tin. Acryleäureaethylester is in dimethylformamide with and Made on the following additives and aged for 16 hours at 80 °. The following extinctions are then used in the Blko photometer:

E / d at λ - 450 470 530 620 ψ

without addition 0.327 0.250 0.061 ü, 0i5

with 0.05 t Ae 0.284 0.222 0.052 0.018

with 0.1 £ SO ₁ - (CHe-CH ' ⁰⁰⁰⁰⁰ *), + 0.05 * Ae 0.161 0.128 0.033 0.006

^N C0CH ₈

with 0.25 f> "+ 0.05 " h Ae 0.167 0.138 0.032 0.005g

with 0.5 % j) + 0.05 £ Ae 0 _fc 174 0.134 0.042 0.014

(Ae = ethylenediaminetetraacetic acid)

Example 4 :

A 10 # solution of a copolymer of 95 TIn. Acrylonitrile and 5 Hn methyl acrylate is in dimethylformamide with and o & ne made the following additives and aged for 16 hours at 80 °. The following extinctions are then measured in the electrolytic capacitor:

B / d at Λ - 450 470 530 620 oytj

without addition 0.300 0.234 0.073 0.026

with 0.05 f Ae 0.264 0.211 0.075 0.027

with 0.25% C, H, S-CH.-ΟΗ ^ ⁰⁰ ' ⁰¹¹ »^, + 0.05% Ae 0.227 0.173 0.053 0.021

^N CO-CHf

(Ae = ethylenediaminetetraacetic acid) From all these experiments it can be seen that the extinction of the solutions stabilized according to the invention after aging is considerably lower than the extinctions of the unstable! The solutions according to the invention have thus "It" enig.r vrttrtt. 909821/1162

ORIGINAL INSPECTED Le A 7633

Claims (3)

Patent claims: 1) Process for the preparation of solutions from acrylonitrile polymers in "organic solvents in the presence of stabilizers, characterized in that the dissolving process is carried out in the presence of a compound of the formula R ₂ makes in which R Urd Rp for water toff, are alkyl and aryl, R ^ sulfonyl, hydrogen, alkyl, or a polar polarisferFären radical, such as phenyl, halogen, cyano, keto alkyl, carbalkoxy, and alkyl is, for a polar or ierbären R. Polatis ~ Radical, such as phenyl, halogen, cyano, ketoalkyl, carbalkoxy and alkylsulfonyl, R ₁ - for> any organic radical, preferably for ^{X is} CH -C-, ^R 4 ' ^R 2 / in which R ₁ "to Rr have the meaning given and Λ. r. for Ο; 1 or ?. stands. ' 2) Process according to claim 1, characterized in that one works in the presence of complexing agents for heavy metal ^. Le A 76 33 909821/1162 BATH ORIGINAL / S " 3) Process according to claim 1 and 2, characterized in that one works in the additional presence of sulfinic acids. La A 763 3 909821/1162